The valve version of the Isis Reference CD player
Rega Valve Isis is a Reference CD player with valve analogue section, twin Wolfson DACs, galvanically isolated USB input and transformer-coupled balanced output.
Valve Isis shares its digital and USB section with Isis but replaces the solid-state analogue stage with valve circuitry and passive filtering. Digital-to-analogue conversion uses two Wolfson WM8741 DACs, while the output stage employs two 5814A triodes of triple-mica, military-specification type, equivalent to ECC82/12AU7. The transformer driver and output buffer additionally use two ECC88 triodes, in a configuration developed to retain precision and articulation without turning the design into a simple tonal effect.
Key features
- Advanced Rega CD technology
- Twin Wolfson DACs
- Rega K-Power reservoir capacitors
- Custom-designed Reference chassis
- Reference CNC remote control
Valve analogue stage
The DAC's differential output drives a valve differential amplifier where a small amount of feedback stabilises operating conditions. The path continues through the transformer driver and output buffer, also valve based. Component choice and passive filtering are intended to preserve signal integrity, while the balanced output uses a dedicated transformer consistent with the player's valve topology.
Digital section and power supplies
The digital section uses a selected mechanism matched to the servo circuits, with separate power supplies for the motor, user-interface processor and display. The digital section has a dedicated 50 VA transformer and numerous local regulators, while critical circuits use Rega K-Power capacitors and fast diodes. Board layout separates digital and analogue areas and limits interference from service circuitry, keeping the audio path as isolated as possible.
USB and disc analysis
The USB input lets a computer use the internal DAC through an isolated dual-clock interface with its own regulated power supply. Galvanic isolation reduces ground currents and noise generated by the computer. During initialisation the player also analyses each disc and adapts CD-processor control to the characteristics of the medium, with the aim of optimising reading, tracking and error correction where required.
Supplied accessories
The Reference CNC remote control is included.
